# High-Performance Multifunctional rPA6/rCFRP/rGraphite Hybrid Composites from Recycled Industrial Waste

## TL;DR

This paper shows how industrial waste materials can be turned into strong, electrically conductive composites for practical applications.

## Contribution

A novel approach to upcycle industrial waste into high-performance hybrid composites with mechanical and electrical properties.

## Key findings

- rPA6/rCFRP composites achieved 126 MPa tensile strength and 4.8 GPa modulus at 20 wt% filler.
- Hybrid composites showed electrical conductivity between 10–5 to 10–1 S·cm–1, suitable for antistatic uses.
- rGra improved processability compared to rCFRP, making hybrid formulations more practical.

## Abstract

Environmental concerns and the global shift toward a
more sustainable
and circular economy have increased the demand for economically viable
materials derived from industrial waste. In this study, high-value
engineering materials discarded from different industries were repurposed
to develop new multifunctional hybrid composites. The selected postindustrial
waste included polyamide 6 (rPA6) from automotive plastic washers,
recycled graphite (rGra), and recycled carbon fiber reinforced polymer
(rCFRP) epoxy-based composites originating from the aerospace sector.
These materials were separately ground using a knife mill and subsequently
compounded via extrusion. The fillers (rGra and rCFRP) were incorporated
individually and as hybrids (rCFRP:rGra, 1:1 wt %) at total loadings
of 5, 10, and 20 wt % in the rPA6 matrix. The composites were characterized
in terms of morphology, rheology, mechanical performance (tensile
test), thermal behavior (differential scanning calorimetryDSC),
electrical conductivity, and electromagnetic properties. The mechanical
results revealed a notably high ultimate tensile strength of 126 MPa
and an elastic modulus of 4.8 GPa for the rPA6/rCFRP (20 wt %) composition,
suggesting strong interfacial adhesion promoted by secondary interactions
between the epoxy resin coating on the rCFRP and the rPA6 matrix.
Electrical conductivity measurements on composite films showed values
from 10–5 to 10–1 S.cm–1 for the hybrid and rCFRP-filled compositions, indicating their potential
for antistatic (anti-ESD) applications. Although rGra exhibited lower
mechanical and electrical performance than rCFRP at the evaluated
contents, it was less detrimental to processability, making the hybrid
formulations more balanced candidates for real-world applications.
Overall, this study demonstrates a promising strategy for upcycling
industrial waste into high-value, multifunctional composites, thereby
contributing to resource efficiency and waste minimization across
various industrial sectors.